Karthik Nayani

NayaniDr. Karthik Nayani

Detection of flaviviruses and coronaviruses

Today, the warming planet is playing a central role in driving the resurgence and redistribution of infectious diseases across the globe. In this context, in addition to identification of specific pathogens, it is also crucial to screen for classes of pathogens, such as enveloped viruses, to keep track of new and emerging health threats. To address this need, we employ liquid crystal-based sensing principles to detect flaviviruses and coronaviruses. These viruses include COVID-19, West Nile, Zika, Dengue and SARS, some of which are associated with widespread morbidity and mortality throughout the world.  Flaviviruses and coronaviruses are both enveloped viruses, but they have complex macromolecular organizations that are distinct between themselves and different from other classes of enveloped viruses. More broadly, a range of fundamental questions regarding the interactions of virus-specific lipid/proteins with liquid crystals need to be resolved to enable rational design of biosensors for viruses based on liquid crystals. Different confined geometries of liquid crystals, including thin films, droplets and microfabricated wells will be employed to explore and optimize sensing strategies for viruses.

Using anisometric mechanical strain on cell membranes for single cell analysis

It is known that changes in mechanical properties of biological cells, for instance, red blood cells (RBCs), play a profound role in physiological processes. For instance, increased stiffness of sickle cells reduce the lifespan and the ability of blood cells to flow through narrow capillaries where they commonly encounter anisometric strain. Furthermore, the stiffness of mammalian cells has been shown to be a marker of the metastatic potential of cancers. We study the deformability and relaxation of cell membranes when subjected to anisometric strain using an ordered fluid, specifically, lyotropic chromonic liquid crystals (LCLCs), as a host. LCLCs are a class of polyaromatic dyes that are soluble in water and form supramolecular semi-flexible rod-like assemblies upon solvation. The water solubility and bio-compatibility of LCLCs make them suitable for biological applications. In addition we are also interested in the phase behavior of LCLCs as a function of different counter-ions will also be explored using a combination of microscopy, rheology and scattering techniques.  This will enable studies of biological membranes in the presence of specific cations that are known to influence cell membrane properties.